horn with slant polariztion(45,-45 polarization)

[ferdows]

hi
"when horn antenna rotated the antenna polarization change to slant from vertical or horizontal "
how we can design horn antenna with slant pol with out rotation ?????????

 

[eagle5]

You can use a square-pyramidal horn with two ortoghonal probe feeds with the proper phase difference.

 

[ferdows]

hi
yes it may be possible but i look for simple technique because phase shifter design is difficult and antenna became expensive and process became hard

 

[plasma]

if you don't need ±45° polarization at the same time you can build 2 slant linear polarizer (±45°) and switch between them.
this keep the beamwidth that you need.

 

[eagle5]

What about using a circular horn feed through a circular waveguide with the probe-feed at 45º?

 

[ferdows]

hi thanks every one
i try the all method u said like polarizer and 2 antenna and like this
about circular u should notice to this when u rotate horn antenna all polarization detected by this like vertical horizontal and RHCP and LHCP but when u using circular like RHCP it cant receive from LHCP and that ids the weakness of circular polarization

 

[RCinFLA]

but when u using circular like RHCP it cant receive from LHCP and that ids the weakness of circular polarization

Weakness? same applies to a linear polarization when tx and rx are 90 degrees.

Circular polarization has an advantage that any reflected version is opposite circular polarization. GPS uses this to reduce multipath reflection interference from items in surroundings.

 

[ferdows]

hi
if u want a detection radar and for this if u use circular polarization with out rotating u cant achieve good result

 

[eagle5]

What I mentioned was to use a circular horn antenna, NOT circular polarizarization. A circular horn antenna fed with a circular waveguide with the dominant mode TE11 produces linear polarization.

 

[ferdows]

hi eagle thanks a lot for your favor
did u ever check it or design like this or seen same antenna? TE11 design is difficult and need some element like a metal at aperture of circular wave guide to convert TE01 to TE11
i know that higher mode in horn antenna made circular polarization

 

[eagle5]

TE11 is the dominant mode in circular waveguide, actually its field distribution looks like the TE10 in rectangular waveguide. You can excite this mode just by feeding the waveguide with a probe, exactly the same as in TE10 rectangular waveguides.